1. Field of the Invention
This invention relates to improved eye glasses for use by people with macular degeneration, optic nerve damage or similar low vision problems and; to the lens assemblies, per se, used in such eye glasses.
2. Description of the Prior Art
Various types of apparatus have been deviced for people with vision problems. The most common of such apparatus are eye glasses for helping people who have difficulty in focusing light rays of an object being viewed onto the macular retinal membrane on the rear of the eyeball. Inadequate focusing is not uncommon and is caused by the improper focusing by the cornea and lens of the eyeball. When the cornea and lens do not function to properly bend or refract the incoming, image-bearing light rays, such light rays are not properly focused upon the macular retinal membrane and, as a result, the optic nerves cannot convey the proper information to the brain to effect proper vision. Mechanical lenses can normally correct this type of vision problem. Such mechanical lenses normally take the form of contact lenses, eye glasses or the like and have been in common usage for many years.
When, however, faulty vision is caused either by the degeneration of the whole or a part of the macular retinal membrane on the back or interior face of the eyeball, or by the deterioration of the optic nerve which would normally carry the images from the macular retinal membrane to the brain, standard lenses themselves are insufficient to restore proper vision to the patient so afflicted. Surgery might be a solution. Alternatively, additional intensification of the light within the image pattern may in some cases effectively restore sight.
Various commercial devices for overcoming low vision problems have recently received commercial acceptance to varying degrees. One of these devices is the Finebloom System. The Finebloom System is constructed of tube-type devices consisting of mirrors that attach to a conventional pair of eye glasses. This apparatus allows a patient using such system to focus on objects at one particular distance. The mirrors of the tubes intensify the focused light to allow the degenerated macular retinal membrane, or degenerated part thereof, or the deteriorated optic nerve to function again to thereby effectively restore vision. Different tubes must be utilized for focusing at different distances. Unfortunately, such a system allows only about ten percent peripheral vision thus reducing the user to pinpoint or tunnel vision.
An additional low vision aid recently introduced to the commercial market is the Opticon System. This system consists of diverging contact lenses of a negative power used in optical cooperation with additional conventional converging lenses of a positive power. The positive lenses must be moved toward or away from the contact lenses and eye of the user to focus in a manner similar to a telescope. Patients utilizing such a system have a wider field of vision than they would experience with the Finebloom System, but magnification becomes a problem. Vertex distance, or distance from the contact lens of negative power to the front of the forward lens of positive power, creates a telescopic image much larger than normal size. This results in a depth perception problem for the user. Objects being viewed thus appear much closer than they really are. Further, as a practical matter, a great percentage of users of systems of this type are older and encounter problems applying and removing their contact lenses.
Various prior art disclosures described lens arrangements in combinations which have limited structural similarities to the lens arrangement of the present invention. The original telescope by Galileo, for example, utilized a negative power lens close to the eye of the user in optical combination with a positive power lens supported by a tube at fixed distance from the negative lens. In later telescopes, the distance could be varied by the user as a function of the distance to the object being viewed. In the telescope of the later type, unlike the lens system of the present invention, the distance between the functioning lenses varied. There was no specific provision for image intensification as would be needed for people with low vision problems as described above. Futhermore, the telescopes of Galileo, as well as of later types, were designed for magnifying rather than for achieving the effective one-to-one focusing which is the objective for normal eye glass use.
Other lens arrangements which utilize combined lenses of positive and/or negative characteristics are found in U.S. Pat. Nos. 2,474,837 to Glancy and 3,511,558 to Uberhagen. These disclosures are directed to apparatus for use as magnifiers as in telescopes or cameras, a totally different function than the present invention which seeks to retain a one-to-one imaging with increased illumination over a range of distances for correcting low vision problems. Even though structural similarities may exist between the present invention and these prior art devices, their structural dissimilarities preclude their use for the purposes of the present invention.
Additionally, other prior art disclosures which describe lens arrangements for eye glasses can be found in U.S. Pat. Nos. 968,693 to Rohr; 2,092,789 to Tillyer; 3,702,218 to Manhire; and 3,877,978 to Tolar. In all of these prior art disclosures, the lens assemblies are directed to combinations of lenses of varying shapes and powers to correct the problems a patient may have in focusing light rays onto the macular retinal membrane as caused by an improperly functioning cornea and lens. None of the prior art arrangements of lenses provides for the light intensifying capability to help patients who have low vision problems as caused by macular degeneration, optic nerve damage or the like. In most cases, these prior art patents describe lens arrangements which combine their positive and/or negative lenses together into a single lens. They therefore function as a single lens solely for the purpose of improving the focusing capabilities of the patient. Further, as discussed above, even though structural similarities may exist between the present invention and these prior art devices, their structural dissimilarities preclude their use for the purposes of the present invention.
Although many lenses and other optical devices in various combinations have been proposed in the past for overcoming a wide range of optical problems, none teaches the present inventive use of eye glasses having lenses of positive and negative powers, separated by a fixed air space and incorporating a prism for their purposes, objectives and advantages of overcoming macular degeneration, optic nerve damage and simlar low vision problems. The present invention overcomes the problems of the prior art and achieves its objectives and advantages with a minimum number of functioning parts and at a minimum of cost. The present invention also eliminates both the need for a patient to endure tunnel or pinpoint vision and eliminates the need for a patient to wear a bulky apparatus or one which would require constant readjustment for focusing. These objectives and advantages should be construed to be merely illustrative of some of the more prominent features and applications of the present invention. Many other beneficial results can be attained by applying the disclosed invention in a different manner or modifying the invention within the scope of the disclosure. Accordingly, other objects and advantages, as well as a fuller understanding of the invention, may be had by referring to the summary of the invention and the detailed description describing the preferred embodiments of the invention in addition to the scope of the invention as defined by the claims taken in conjunction with the accompanying drawings.